Note on pronouns. If Dusk thinks about things he did while he was Twilight he will use ‘she’ or ‘her’ in self-reference rather than ‘him’ or ‘he’.

I've also tried a bit of an experiment, showing the same scene from Dusk's realistic POV, and Pinkie's POV with extra added scary goodness.

The party always ends. That was a simple fact of life. No matter how much food you order, or how many guests you invite, sooner or later the party ends. And when it does everypony will go back home, and you get to go back to your lonely empty room till the next day and the next party.

That had been Pinkie’s life. Long sustained periods of joyful maniac activity, followed by short periods of near crippling loneliness.

That was one of the reasons Pinkie had been so eager to learn adult games. She had noticed that Berry Punch’s parties with stallions tended to last through the night and into the wee hours of the morning, and seemed to include sleeping together with her guests. Pinkie’s reasoning went that if she were to add adult games to her repertoire not only would she be able to make grumpy stallions smile, she could turn her own life into one long unending party that would never, ever, end. She’d never be alone again.

And it had worked, sort of. It had been wonderful learning how to play adult games with Dusky. There had been a lot of fumbling and stumbling, but in the end the two of them had fit together as if they’d been made for each other. And most wonderfullest of all, though the feel of Dusky’s big thingy slipping and sliding in and out of her little woohoo had been pretty darn wonderful, was the feeling of falling asleep wrapped in Dusky’s arms and wings and then waking up to find him looking her in the eyes and greeting her return to the world of the awake with a deep kiss, followed by yet another splendiferous wonderiffic session of adult pony play.

Having mastered the basics, Pinkie had been looking forward to taking her new found skills out into Ponyville. Only, there had been a few problems. The first was that every stallion she targeted took off for the hills as soon as he saw her coming. It wasn’t just the ponies she’s propositioned, incorrectly, earlier either. Pipe Layer, who Pinkie hadn’t even talked to since she’s thrown him a birthday party nearly a month before, had jumped right out of the trench he’d been working on and walked quickly away from her, dropping his tool in the process. In retrospect picking up the heavy wrench and running after him while waving it over her head might not have been the best idea in the world. Given the way he’d run right into a wall while looking over his shoulder at her.

The second problem was that none of those stallions were Dusky. It was wrong of her, Pinkie knew that. You couldn’t throw parties for just one pony all the time. If you were a party planner pony you had to throw parties for all the ponies. Just like Rarity could not make clothes for only one pony, or Applejack couldn’t grow apples for just one pony. You had to share the fun with as many ponies as you could.

And it wasn’t that Pinkie didn’t want to play adult games with other ponies. It was just that, well, she wanted to do it alongside Dusky. She just couldn’t imagine playing any of the scary cool games from those wicked cool game books of Twilight’s without Dusky there to play the big bad monster. It was a lot like how after seeing Princess Luna do it once you couldn’t imagine anyone else playing Nightmare Moon but her. She was so scary perfect at it.

But Dusky was going to go away soon. Pinkie really hoped that Twilight would let him come out again, a lot, to play with Pinkie, but she couldn’t help but worry that maybe Twilight wouldn’t. The solution seemed fairly simple, fortunately. All Pinkie had to do was make sure that Twilight had so much fun being Dusky that she’d want to play lots and lots in the future as him.

“So why am I running around Ponyville chasing after other stallions when I got the scariest stallion of them all already?” Pinkie suddenly yelled out in the middle of the street, causing all hoof-traffic around her to come to a sudden screeching halt.

The ponies around Pinkie Pie exchanged looks, there was a communal session of shrugged shoulders and eye-rolls, and the unspoken consensus of, “it’s just Pinkie being Pinkie,” and everypony went back about their business leaving Pinkie panting in the middle of the street, her sudden self-revelation making her eyes glow with determination. With no further vocal outbursts she turned around and headed back toward the Palace of Friendship.

Dressed only in an over-sized lab coat; that Twilight had acquired from Rarity on the off chance that Princess Celestia might show up one day and want to work in the lab with her, Dusk Shine puttered away at his latest Pinkie Sense sensor. As he fiddled with the project Dusk Shine contemplated the strange workings of fate. It had been two days since the first time he and Pinkie had ‘done’ it and he still couldn’t believe he’d had sex as a stallion, and now had a marefriend; at least till he stopped being a stallion, and then who knew. So far it had been a pretty wild ride, literally. Despite the short period of time involved he and Pinkie had indulged in hot steamy sex at least a... Dusk checked a nearby checklist. “Dang! Pinkie’s taken me orally twelve times and fifteen vaginally. Of course five of those started out oral, but moved to vaginal before I ejaculated.” he muttered, considering adding another check box for that combination. At the same time he wondered if that was a large number of sexual encounters? An average one? A below average amount?

According to the reference books, and several adult joke compilations, it wasn’t unusual for a stallion and his marefriend to copulate frequently and with great vigor during the period that occurred directly after consummating their relationship for the first time. But, Dusk had to believe it was much more unusual when the stallion in reality was a total geek who had zero experience with mares, and, oh yeah, was actually an Alicorn Princess who was just temporally trying on a stallion’s body for size and comfort; purely in the name of scientific inquiry, of course. He credited Pinkie Pie. He’d have never have had the nerve to even suggest such behavior without her pushing, and shoving, and giving him those long sad-eyed looks.

To his great surprise, he was finding being male instead of female a surprisingly comfortable fit, once he’d stretched his mind around the concept and consequences of being a smoking hot stallion with a libido that at times tended to derail his higher mental functions. Well, to be fair, it wasn’t just being a stallion. He had the feeling he’d be having the same befuddled sensation even if he was female. So long as it included playing adult games with Pinkie Pie. The new dynamic between him and Pinkie made it difficult to think about much else. Even when she was not with him he found himself spending most of his time trying to think up things that would make the party pony pleased.

Not that unusual in some ways, he had always been on a constant lookout for things that would interest or intrigue his friends. The major difference was the sort of things that caught his attention after learning what made Pinkie purr with pleasure. For example, he had been doing some research on that topic and found himself looking at the candle whose light he was reading by, and suddenly found himself wondering how Pinkie would feel about him dripping hot wax on various sensitive areas of her body. That was a frequent fetish illustrated in the restoration books. As was inserting the lit candle into a mare’s bottom. That last he could safely mark down as pure fantasy. No mare would find that in the least little bit fun, not even Pinkie.

Or would she?

Dusk let out a growl of frustration. The simple fact was that when he looked at the Restoration books from a mare’s point of view, he couldn’t help but think that there was no way any mare would ever enjoy any of the things depicted in them. But he knew for a fact that this was not the case. Even before discovering Pinkie’s kink he had known that there were some mares who got sexual pleasure out of assuming the role of slaves. He hadn’t understood it, but he had known the fetish existed. Now that he knew Pinkie was one of those mares he very much wanted to make her happy, if he could just figure out the best way of doing it.

The truth was that Dusk was afraid that if he continued to allow Pinkie to take the lead, she’d grow tired of his lack of mastery and go looking for a stallion that was better at it than he was. The very thought of Pinkie dumping him for another stallion left him feeling hollow inside. That was why he had spent so much of his free time researching the Restoration books like never before. There were no end of ways to sexually torture mares discussed in the books, with many illustrations for the literary challenged. The real problem was he had no idea what would make Pinkie terrified in the way she liked, and were actually realistic, and which would cross the line into, “You monster. I never want to see you again!” territory.

For instance, ice. That seemed simple enough, and he could see how it might be arousing to a mare to have a cube rubbed on her nipples and even her clitoris for a short period of time. But how could a mare enjoy having a artificial phallus made of ice inserted into her rectum and vagina. The mares in the restoration books certainly were not depicted as enjoying the procedure. But you could say the same about most of the illustrations in the books. The creators of the books were only interested in dominating mares. they cared nothing for their victims pleasure. But he knew that Pinkie took great pleasure from some of the activities illustrated there, such as getting spanked with a ruler.

Dusk Shine’s current project was a perfect illustration of his problem. He had started out with the goal of combining the scientific utility of a body probe sensor with the kinky fetish aspect of a sex toy. The result was sitting on the bench in front of him. A heavy glass sculpture crafted from tempered laboratory glass with wires and sensors embedded inside it. The sensors had been crafted to look like multi-colored balloons, while their copper wires performed double duty. First they looked like strings tied to the bottom of the balloons. Secondly they transmitted data. It was beautiful in an artistic and scientific sense, and Twilight thought Pinkie would love it. But what if she didn’t? They hadn’t even discussed anal sex play. How would Pinkie react to him giving her a glass butt plug as a gift? Would this cross the line from good dirty fun to you're a freak city?

“Youuuu huuuu, Dusky, are you down there,” Pinkie Pie’s voice echoed from the head of the stairs that led down into Dusk Shine’s lab, or his deep, dark, despicable, dungeon according to Pinkie Pie.

Dusk felt a happy pulse of pleasure at the sound of his marefriend’s voice. A most strange feeling, far different from the feeling Twilight got anytime she was with Princess Celestia, but one he was becoming highly fond of. Without really thinking he called out. “I’m here, Pinkie Pie. Come on down.” Not that the invitation was really needed considering he could already hear Pinkie’s hooves clattering on the crystal staircase. A moment later his eyes flew wide and he snatched up the heavy glass artifact he’d been working on and looked around frantically for some place to stick it out of sight. In the end he ran out of time and found himself standing with it held behind his back and tucked under his tail, as Pinkie bounced into the room.

For a moment all Dusk could focus on was how much more fun it was to watch Pinkie bounce now that he was a stallion than it ever had when he’d been a mare. He watched mesmerized as she came straight toward him, her balloon like breasts seeming to move independent of the rest of her body. Their hypnotic effect lasted till Pinkie stood on the tip of her hooves and gave him a quick kiss before asking, “What chu hiding,” in a cute sing-song tone as she tried to peek around behind Dusk. She pressed up close to him and slipped her arms around his back.

Dusk was so worried about Pinkie’s reaction to his project that he could barely appreciate the way her breasts flattened against his chest. “Nothing. Just a little project I was working on. Nothing you’d be interested in,” Dusk stammered. He was glad his male body was large enough that there was no way Pinkie could possibly reach the perverted glass sculpture.

“Oh, how cute. I love it,” Pinkie Pie squealed holding up the heavy glass butt plug and admiring how the overhead lights shone through it. “And it has balloons in it.” She waved the object through the air. “Look, they seem to float all by themselves.”

“What? How? Where?” Dusk sputtered pulling his hand out from behind his back and looking at the heavy glass flask in it.

“Oh, I can’t wait. I want to try it right now.” Pinkie gushed.

“Right now?” Dusk said in a strangled tone. Under his lab coat his wings quivered as they started to stretch out, while between his legs he felt his male member starting to stand equally to attention.

“Uh huh,” Pinkie nodded. She bent over the nearest desk, thrusting her ass out toward him as her tail swished back and forth.

Dusk Shine’s breath caught in his chest and his eyes twitched in tandem as he found himself mesmerized by Pinkie’s swishing tail, and what it revealed and concealed as it moved. Like a zombie he lurched toward her as if being dragged by a force he could not resist.

“There, isn’t it pretty,” Pinkie gushed. She stood aside to show the stack of papers she’d pulled into one bundle, and the heavy glass butt plug sitting on top of them holding them in place. “And it works so well too. I can’t wait to show Mrs. Cake. Why just the other day Derpy flew into the shop and the gust of air blew the receipts all over the place.”

Dusk almost fell on his face as his lurch forward threatened to turn into a face-plant. “What? No! I mean, I don’t think... It’s not. It’s...” Dusk flailed trying to find the right words to explain just why it would be a really bad idea for Pinkie to use her present to hold down papers in Sugarcube Corner. Visions of the Cutie Mark Crusaders interrogating Pinkie Pie about it danced in his head. Followed by a vision of the Royal Guards dragging him off to jail for corrupting the innocent.

“I’m just lucky you’re not an evil meany, or you’d likely shoved this cute thing up my pooper,” Pinkie said without a single shift in her tone or delivery.

Pinkie watched with interest as Dusky’s expression ran the gamut of emotions, from blank, to dawning awareness, to annoyance at himself for falling for Pinkie’s gag, and finally to speculation and outright lust. The last was easy to make out, it was accompanied by the back of Dusky’s lab coat bulging out as his wings fought to spread while at the same time his big thingy started to get a lot more thingy.

Pinkie had always enjoyed messing with Twilight. Messing with Dusky was even more fun than seeing how long it took for Twilight’s head to explode, because Dusky’s explosions tended to be much more interesting, and tasty to boot. The, play adult games, game had turned out to be a huge success. Dusky had really made an effort to learn the rules and special language that you needed to play the game well. He still fumbled a lot, but then Pinkie knew she herself had a whole lot to learn herself before she could be considered a master player. But that was the fun thing about games. Learning to play them was just as much fun as playing them once you mastered the intricacies.

Case in point. Dusky had finished wrapping his head around Pinkie’s unsubtle suggestion, and was now doing his best to slip into game mode. “Well. That is too bad. Because you have made a bad mistake you foolish, foolish, pony,” Dusky said, in a slightly hesitant voice as he kept glancing at a notepad on the bench behind him. “For know this, I am not who you think I am. I am in fact, Dusk Shine. Twilight Sparkle’s evil twin brother from another world. On the other side of a magic mirror.” Dusky took a look at his careful notes and finished off with an evil laugh. “Bwa Ha Ha,” he took another quick glance, “Hah.”

Pinkie knew her cue. “You’ll never get away with this you evil nasty fiend. I’m going to run away now with all my might and get my friends...” Pinkie paused and made a mental note to recruit some of their friends for a group game as soon as possible, and then resumed. “We’ll put a stop to your dastardly deeds.” She turned around, flicked her tail dismissively at Dusky and hopped toward the exit.

“Not so fast my pretty pink pony,” Dusky said, actually putting some real menace in his growl. “You’re not going anywhere until I say so.” His magic reached out and enveloped Pinkie. She was picked up off the ground and floated back toward him.

Pinkie bucked and crawfished with all her might, but was unable to break free of Dusky’s magic. She felt a thrill of make-believe dread at how helpless she was. She thought she might be able to slip from his hold, if she really, seriously, wanted to do so. But, it was that maybe that made it so scary good. She ‘knew’ no unicorn could hold her if she didn’t want to be held. She wasn’t sure about Dusky. Yet another reason no other stallion could be nearly as fun to play with as the alicorn stallion. “No, you terrible awful mean pony. You can’t do this to poor helpless little me. Do you have no compassion? Do you not have a sister, or a mother? What would they think about what you are doing?”

“Hah, don’t you know. There is a good reason why they call me a mother-fucker,” Dusk said, and then blushed crimson and slapped a hand over his muzzle. His wide eyes said as clearly as if he had spoken, Did I say that out-loud.

“Ooh, good one,” Pinkie congratulated him.

“Really? It wasn’t a bit much?” Dusk asked, his cheeks still dark purple from embarrassment.

“Nah,” Pinkie assured him. “It’s just the sort of thing an evil meany would say to a poor helpless filly in his clutches.”

“Okay then,” Dusk Shine said. He closed his eyes and took a couple of deep breaths. After a moment he opened them up and glared at his helpless captive.

Dusk opened his mouth to say his next line, and was cut off as Pinkie suddenly shouted out. “Sugarless! Sugarless!”

Dusk stopped cold and let his magic field evaporate while he asked. Hesitantly he asked, “Did you mean sugar free, Pinkie?”

Pinkie frowned. “I don’t know. Which one means stop a minute, and which one means don’t pay any attention to the pony crying for mercy?”

“You said in your note that sugar free was the safe word,” Dusk Shine said. “So do you want me to continue?”

“That’s the one. Don’t I feel silly. Sugar free. Just hold on for a minute. I have something we just have to have before we go any further.” Pinkie rummaged around in her mane for a moment before extracting a heavy wrench that was almost two feet long.

Dusk Shine’s eyes went wide and his face paled. From the way his gaze flickered back and forth between Pinkie and the wrench he was clearly wondering just what she expected to do with the lethal looking thing. Or even worse, what she expected him to do with it.

“Oh, don’t be such a scaredy-cat Dusky. I picked this up after Pipe Layer dropped it. Remind me to get it back to him.” Pinkie set the blunt instrument down on a bench next to the large flask holding the poison joke neutralization bubble bath solution while she rummaged around in her mane a bit more.

“Ooooh, I forgot all about this,” Pinkie squealed as she pulled out a soft rubber ball that she’d threaded a rope though. “We needed a ball gag to play some of the games in the manuals, but I didn’t know where to buy one, so I made this.”

Pinkie tossed the home made sex toy to Dusk who juggled it a bit before getting a firm grip. It was a standard foal toy. Nothing special. But it was huge, at least for what Pinkie intended to use it for. He looked at it trying to imagine how even Pinkie could fit the thing into her mouth. He flexed his fingers and the soft rubber deformed in his grip. It was sort of squishy, so that might help. It should mould itself to fit. He squeezed again, muttering to himself as he tried to calculate the compression factor. A moment later Dusk gave his head a shake, while muttering in a low voice, “Pinkie is my friend, not a science experiment.”

“But I like being a science experiment,” Pinkie said, popping up right under Dusk’s nose. “Look, I found it,” she added, holding up what looked like several dead woolly caterpillars.

“What are those?” Dusk asked as he reared back from the thing Pinkie was trying to push against his muzzle.

“It’s a mustache, silly. All evil twins have to have facial hair. Geh, don’t you know anything, Dusky?”

“Really? I’ve never heard that,” Dusk said while still trying to keep his muzzle away from Pinkie’s hands.

“Oh, sure, well known fact. Now hold still while I...There, all done,” Pinkie sang cheerfully as she pressed the various bits and pieces to Dusk’s face. Once she was finished she gestured toward the big full length mirror in the corner of the lab. “Take a look Dusky. Don’t you look evil as all get out?”

Dusk Shine hesitantly took a look at himself, and for a second could almost see what Pinkie meant. The strips of hair did make him look rather nasty, but then one of them peeled off the side of his muzzle and dangled down, and he went from looking saturnine to the victim of some hideous disease.

Not a sexy image.

When Pinkie reached out to re-position the errant strip of hair Dusk waved her off. “Don’t worry Pinkie Pie. This at least I have. Thanks to Spike I mastered the mustache spell a long time ago.” There was a tiny bit of boasting in his statement, for all his professed modesty he did like showing off his skills to someone who would appreciate them. And he had a feeling Pinkie would be a very attentive audience for this trick.

Dusk peeled off the remaining fake mustache parts and focused on the mirror as he cast the appropriate spell. A moment later he had a huge handlebar mustache decorating his face. Pinkie burst into laughter and Dusk had no problem understanding her reaction. He looked like someone’s blowhard-uncle. The sort who made holiday dinners such a chore. Not that he had any such relative, but they were a staple in fiction books, and politics. It was not the look he was going for. A flash of light and that abomination disappeared and was replaced with something much closer to what Pinkie had been trying for.

“How’s that Pinkie?” Dusk asked, turning his muzzle from side to side while he examined the thin narrow mustache that drooped just below his jawline along with a small narrow goatee decorating his chin.

“That’s great! Only, you need a bit more under the chin. So you can tug and stroke on it when scheming your evil schemes,” She said. She made downward motions under own muzzle to illustrate the effect she was suggesting. Dusk nodded and refined the spell. A moment later a six inch waxed tendril of a beard extended about six inches below his chin. He reached up and gently tugged on it, stroking it between his fingers till the tip curled upward slightly.

“Ooooh, perfect!” Pinkie cried out. “You look like your big brain is just chock full of plans to overthrow the kingdom and rule with an iron hoof. I can just see you tossing Princess Celestia and Princess Luna in the dungeon where you would do horrible awful things to them until they agreed to marry you and give you legitimacy to rule. And then you’d capture me and all my friends and put us in your harem and do horrible, awful, wonderful, things to us till we agreed to be your eternal love slaves.”

Dusk Shine blinked. “That’s rather... detailed. Been thinking about this for awhile?”

“Nah. Just popped into my head.” Pinkie drew a deep breath and said very firmly. “Lots and lots of sugar.” Then, in case Dusk did not get it she added. “That means game on, Dusky.”

“Eh? Oh, Right.” Dusk gave the mirror a last look, trying to get into the head of the villain that Pinkie wanted him to be. In the corner of the mirror he spotted Pinkie tip-hooving in a very exaggerated way toward the stairs.

“Where do you think you’re going, cow,” Dusk said in what he hoped was a menacing enough voice.

“Hah. Shows what you know. I’m a pony, not a cow. Get your eyes checked Mr. Nasty Mcnasty.”

“Really. With those ridiculously over-sized udders, it’s hard to tell.”

Pinkie made a rude gesture in Dusk’s direction and broke into a run for the stairs. Which only served to emphasize said oversized udders Dusk noted even as he reached out with his magic field and gathered her up in it.

Dusk grew thoughtful for a moment and made a mental note to give some thought to whether his female side had some latent resentment over the fact that four of her five friends were more zaftig than she was.

“No! Let me go! I’ll scream.”

“Bwhahahaha! Go right ahead. Nopony will hear you.”

“EEEEEEEEEEEEeeeeeeeeeeeeeeeeeeeeeeeeeeeeee!”

Dusk Shine staggered backward and folded his ears flat. He watched in horror as all the nearby flasks, including the one containing the PJNBBS, began to vibrate. Acting quickly he tossed the soft rubber ball gag he was still holding in his hand at Pinkie, and guided it home with his magic.

“EEEE---” Pinkie’s shriek cut off as the ball gag filled her wide open mouth, and Dusk hurriedly tied the cord in place behind her ears. He next restrained Pinkie’s arms when she lifted them with the intent of pulling the ball free of her wide-spread mouth.

Pinkie felt a thrill of fear shoot down her spine. She hated not being able to talk. It was like losing a leg, she felt crippled, only half a pony. But she’d known that would be the case when she’d created the make-shift ball gag. And the results were everything she had hoped for. She felt much more vulnerable than usual as Dusky’s magic restrained her arms.

“That is just about enough of that, you little slut. Time for you to learn some proper respect for your betters.” The words were pretty much a direct quote from a restoration novel, and Dusk was both proud he got them out without either choking on them, or laughing out loud. But he was still worried it was too much. Then he got a good look at Pinkie and saw the way her face lit up at his hackneyed words. A warm glow suffused him as he realized he’d gotten it right. Emboldened, he continued.

“I’m going to enjoy breaking you, slut. And once I’ve got you properly trained I’ll use you to lure all your silly little friends to me so I can do the same thing to them. And you’ll help me do it and thank me for allowing you to aid in their debauching.”

Pinkie felt a sudden liquid heat between her legs and a thrill went through her at Dusky’s words. She also felt incredibly happy to think he was willing to put himself out there that far to make her happy. She well knew that Dusky, like Twilight, was not all that good at, let’s pretend. But that was okay, because Pinkie was a grand master at playing the game.

Okay, Dusk admitted, he’d adlibbed that last little bit, but the flushed excited look on Pinkie’s face caused his confidence to grow. He could do this. He could give Pinkie the sort of experience she longed for. There would be no need for her to seek out other stallions... Dusk’s train of thought trailed off as he realized where it was going. What was he doing? He wasn’t really a stallion, and tonight he’d be taking the bubble bath cure to return to being simple old Twilight Sparkle. This was wrong, he shouldn’t be doing this. He should be helping Pinkie hunt up a suitable coltfriend who could make her happy, not using her like some sort of disposable lab rat.

Uh oh, Pinkie’s pinkie sense warned her, via a sudden chilly feeling at the base of her tail, that she was on the verge of losing Dusky, again. He was starting that old familiar downward spiral where he convinced himself he was being a big meany for having fun with Pinkie, and that it was all because of his stallion juices making him act in silly ways.

Really, as if he needed any help being silly. Sometimes Dusky was the silliest colt imaginable. Not that Twilight was any better. She was always feeling guilty at having random fun for no reason. But right now Pinkie knew that if she didn’t stop Dusky quickly he’d do something silly like tell her that he was so very sorry and that it was unfair to take advantage of her when he would not be able to continue being a stallion for her. Well, she knew just what to do to stop that.

Pinkie kicked him in the shin, hard. The pain shocked Dusk out of his spiraling self-doubt, and the chastening look she directed at him finished the job. Right, this is only a fun game we’re playing. It’s not like I’m really turning Pinkie into my sex slave, or that I’m going to abandon her by turning into a mare. She knows this is not some sort of long term commitment—.

Pinkie rolled her eyes, and re-booted her dim coltfriend again. Maybe this time would do the trick?

“Ouch! Dang it, Pinkie, stop kicking me,” Dusk complained. Pinkie’s only reaction was to take another kick at him. This time he was ready and caught her legs firmly in his magic. Now that he had all her limbs under control she was totally helpless.

Alright. He could be taught, Pinkie Pie thought with satisfaction. Really, for such a smart pony Twilight/Dusky could be dumb as a stump at times.

Dusk Shine couldn’t tell for sure. The makeshift ball-gag distorted Pinkie’s muzzle so much, but he would wager she was smirking at him in self-satisfaction while laughing inside. He let some of the annoyance he was feeling out as he said, “You little minx. You dare think you can toy with the Great and Powerful Dusk Shine! You shall rue the day you dared.” Floating Pinkie gently across the room, Dusk carefully lowered her down on top of the main sensor pedestal and secured her arms and legs the same way he had two days previously. It took him all of five seconds. Practice made perfect. Once he was finished all four of Pinkie Pie’s limbs were firmly secured to the base of the platform that was supporting her torso, and her legs were well spread allowing ready access to her groin.

Pinkie gave a muffled scream into her gag as the fiendish fiend threw her across the room and slammed her down on his diabolical torture device. She hit the rock hard top hard enough to knock all the air out of her lungs and was helpless to prevent him from securing her legs and arms, rendering her totally helpless. She could feel the cool air of his dungeon wafting across her traitorous woohoo which was leaking in anticipation as she found herself wondering if he’d actually carry through and put his fantastic present where it was meant to go.

Dusk found himself looking at Pinkie’s posterior with much less enthusiasm than it deserved. It was all very well to daydream about inserting a sex toy into Pinkie’s rectum. It was a whole other matter to actually do it for real. Still, there was no denying that the very thought of it had made Pinkie light up like a fireworks display. “For Pinkie,” he muttered to himself as he levitated a jar of salve off of a nearby bench. As he did so he could not help wondering if he’d ever be able to walk behind Pinkie again without having lewd and perverted thoughts.

Pinkie struggled with all her might, but the only result was disdain from her captor. He gloated at having her in his power. “Foolish foal, I might have gone easy on you, but now you have raised my ire and will suffer for it.” Reaching out theatrically, Twilight’s evil twin, Dusk Shine, made a beckoning gesture with one hand and a bottle of evil salve jumped from where it was sitting and flew across the room to slap into his hand. Not giving Pinkie time to think about what he was doing he pressed three of his fingers together and used them to scoop out a big dollop of the thick slick substance which he shoved into Pinkie’s ass crack. He twisted his fingers smearing her cleft thoroughly and then folded two fingers back and started to fondle the ring of her rectum. He smirked at the startled whiny Pinkie made around her gag, and outright grinned as her back arched when he thrust a well lubricated finger up her pooper.

Dusk might have been a bit more worried about Pinkie’s state of mind if he hadn’t seen her casually slip out of her restraints after he had keeled over from an overload of stress and sexual release two days before. As it was, secure in the knowledge that Pinkie could escape her bonds if she really wanted to, he began to careful slip his finger in and out of her tight rectum. Only going up to the first knuckle of his finger and gradually slipping more and more of his thick digit up her bottom. Thinking about how uncomfortable it must be for Pinkie, he shifted his hand slightly so his thumb could stroke between the swollen lips of her sex. As he fondled his marefriend Dusk found his breath coming quicker and he felt the now familiar nervous shuddering as his anticipation of what was to come grew, along with his erection. His thick cock was jutted from his groin and brushed against Pinkie’s leg, leaving a trail of pre-cum behind.

Twisting his finger brutally inside Pinkie’s virgin bottom, unmindful of her wails of dismay, the fiendish Dusk Shine added insult to injury by thrusting his thumb into her wet and ready sex. He rocked his hand back and forth, thrusting in and out of both of Pinkie’s openings with no regard for her distress. Her heavily greased ass cheeks made things nice and slippery and no matter how hard Pinkie clenched them she could not stop her awful violation.

“What a slut. You’re dripping like a leaky faucet,” Twilight’s evil twin sneered as he gave his thumb a particularly vicious twist. “It looks like I picked the right mare to start my conquest of Equestria with.” With his free hand he gave her ass cheek a good hard swat before reaching out and gesturing. The butt-plug flew from where it was resting and slapped loudly into his hand.

“Now let’s see how big a slut you really are,” Dusk Shine chortled in glee. He pulled his hand free of Pinkie’s bottom and used the grease on it to lubricate the slick glass plug. “I call this my filly filler,” he said as he used one hand to spread Pinkie’s ass cheeks while using the other to press the tapered tip of the plug against her rectum that was still slightly distended from his finger fucking. Pinkie fought to shift her tail down protectively but the fiend must have used some sort of magic to freeze it in a high arch above her back. No matter how hard she struggled she could not shift it an inch.

Dusk was glad he hadn’t used the restoration books as references when he’d crafted Pinkie’s present. If he had it would have been ten inches long and three inches thick at the widest point. The one he ‘had’ crafted, based on non-fiction sources, was a little over two inches long and only a little over an inch thick at the most. For all of that the glass had a noticeable weight and Dusk was sure Pinkie would be stimulated nicely, especially once he activated the surprise feature.

He pressed the small rounded tip against Pinkie’s relaxed sphincter and maintained a steady pressure. Pinkie let out a little moan, and Dusk saw her thighs clench and her labial lips fluttered slightly. Unless he was mistaken, his helpless victim had just had an orgasm. Which answered the question as to whether it was actually possible to derive pleasure from anal play of this sort.

And that made Dusk consider something he had previously rejected outright in his own mind. Having taken note of how tightly Pinkie’s rear hole gripped his finger he wondered what it would feel like if were to replace that digit with his cock. What would it feel like to ease his penis into the tight humid depths of Pinkie’s little ass? Would she enjoy it? Would he enjoy it? Did he dare to bring it up? Was it an over the line thing? And lastly, why was he even thinking about things like this? He was only going to be a stallion for short periods of time. Given that he had access to Pinkie’s wonderful warm and snug vagina why was he speculating on making use of a different hole?

Unlike his mind, Dusk’s male member seemed to have no doubts as to its preferences. At least based on the way it throbbed and bounced as it grew even harder than it had been before.

Speaking of Pinkie’s gate to heaven. Dusk ran a finger between his friend’s well lubricated folds and drew a shrill, if well muffled, cry from the bound pony. His cock throbbed with his need to sink it to the medial ring inside Pinkie and now that he had filled one of her holes with his gift, he saw no reason not to give himself a little present.

But, before that. Dusk levitated some molten wax from some of the nearby candles. Not to stimulate Pinkie, he still wasn’t sure how she’d feel about that, but to protect himself. Molding the wax as it cooled, he floated two lumps up to either side of his head and inserted them in his ears.

Pinkie squirmed on top of the cruel restraint device. The huge object the fiendish fiend had forced into her defenseless pooper felt like it was going to rip her open, and its heavy weight dragged at her sensitive flesh. Worst of all, he had used his evil skills to force her to orgasm even as he so cruelly abused her. Was there no end to his evil? Of course not. Pinkie felt him shift behind her and something large, warm, and pliable, pressed against her virgin folds. Oh no! He was going to thrust his big thingy into her helpless woohoo and there was nothing she could do to stop him.

“I want to hear you squeal,” the fiend hissed from behind her. Pinkie felt the straps holding the big soft ball inside her mouth loosen. A moment later the ball gag pulled free of her mouth. Instantly Pinkie screamed for help. “EEEEEEEEEEEEEEEEEEuhhhoooooooooo!” Her cries trickled off into a garbled moan as the evil Dusk Shine pushed his over-sized member into her body.

“No, please. Don’t. Stop!” Pinkie begged.

“Don’t stop? Would not dream of it,” Dusk Shine laughed. He pulled back and with a wet squelch before thrusting himself all the way into her, jarring her body and making her breasts jiggle like pudding.

“Oh, boo hoo. You have ripped my virtue from me.”

“A useless thing. The only purpose it served was to prove you hadn’t been previously opened. Now you can take up your true purpose in life. Mares have no higher duty than to provide horny stallions a place to soothe their aching flesh, and a depository for their baby juice,” Dusk Shine taunted her as he continued to furiously rut her. His size stretched her narrow channel to the tearing point and should have filled her with agony. But instead, through his fiendish magic he was forcing her to enjoy her own violation. She felt the pressure build in her belly, and then release in a powerful convulsion that caused her entire body to shudder as she clenched down tightly on his intrusive cock.

Behind Pinkie Dusk Shine gave a startled grunt, followed by a sigh of pleasure and she felt his thick shaft swell and pulse as he filled her womb with jet after jet of his potent baby juice. She felt pressure in her belly as he filled her to overflowing. She could feel her stomach swelling slightly as it pressed against the bench top she was laying on. The mighty flow of stallion juice continued until there was so much jism inside her that it forced its way past the thick plug of her rapist’s shaft and ran down her thighs. Dusk Shine gasped and panted as his thrusting became erratic and after a few frantic off tempo thrusts he slammed himself to the roots inside Pinkie’s ravaged woohoo. His heavy balls slapped against her sperm slicked thighs as her ass flattened from the impact of his hips against her. He pressed hard against her, buried to the hilt as he soaked his cock in her spunk filled vessel.

“Oh, boo hoo. You have ruined me.” Pinkie sobbed.

“And great fun it was. But we are just getting started my pretty pink pony,” Dusk Shine gloated. Without bothering to remove his twitching cock from Pinkie’s overfilled pussy, he used his magic to extract two objects from under a cloth on a nearby bench.

“Oooh, pretty,” Pinkie cooed; breaking character, as two balloon decorated glass objects lifted into view. They looked like short, fat, test tubes, but with thicker glass. The decorations, like the ones in the butt plug filling her ass were inside the glass. Dusky had put some real effort into making them look pretty for her, and that thought gave her a warm glowing feeling inside. Her woohoo tingled as she wondered just what he intended to do with them.

Getting back into character she cried out, “Oh, no, have you not already done enough to me? Have you no mercy?”

“Mercy is for losers,” Dusk Shine sneered as he floated the two objects to either side of Pinkie and then pressed them against her breasts with her nipples inside the wide mouths of the objects. At some point he must have warmed them because they felt almost hot against her skin, and a moment later she felt a pull on her flesh as the trapped air inside them contracted, securing them firmly in place. Pinkie could feel her nipples being sucked inside the glass objects. Totally against her will she felt a flush of pleasure and her woohoo twitched around Dusk Shine’s cock, which had begun to stiffen inside her she noticed. Clearly in anticipation of doing something fiendish to her, again.

By ducking her head slightly Pinkie had a front row seat as Dusk Shine’s magic floated wires from a nearby device to the base of the flasks sucking on her breasts. For the first time she noticed that the glass tubes had small metal studs projecting from their base. The bare ends of the wires wrapped around these. She felt something tickle over her back and knew that another set of wires were being pulled past her tail, and no doubt were being secured to the base of the glass butt plug in the same manner.

Dusk trembled with anticipation, and a little worry. All his tests, on himself, had worked just fine. Pinkie should get a real kick out of this. He was nearly one hundred percent sure of it. But, even so, for just a moment he wondered if he should have talked about it with her first. He dismissed the idea. Talking about a surprise treat sort of ruined the surprise part. He just hoped Pinkie found the treat part of his surprise as much fun as the surprise. Dusk certainly hoped she would.

Pinkie felt the evil Dusk Shine’s cock shift inside her poor abused woohoo, and knew from the way he was hardening he had something fiendish planned. Knowing it had to have something to do with the two evil devices he had just attached to her poor vulnerable personal balloons she kept her head bowed and her eyes fixed firmly on them. There was a click from the nearby cabinet and a sparkly aura filled the two glass objects. At the same time Pinkie felt a tingling feeling coming from her nether regions. Deep in her woohoo her muscles started to twitch like crazy as her pinkie sense sent up a flag. Not a warning flag, an anticipation flag.

There was another click, and Pinkie’s body went into spasms as tiny lightning bolts began to fly from the side of the glass tubes to her nipples, and back again. Shocks inside her rear caused her pelvic muscles to clench and release in time with what Pinkie now knew were more lightning bolts dancing around inside her pooper.

Her orgasm was spectacular.

It was no make-believe scream of terror that Pinkie let out, but a full fledged bellow of delight. “WOOHOO!” She yodeled, her muzzle pointed at the ceiling and her eyes rolled back in her head as her entire body felt like it was on fire with pure bliss.

Dusk wasn’t fucking Pinkie. He was just holding on for dear life and enjoying the ride as his marefriend went into convulsions underneath him. It wasn’t really necessary for him to say anything. It wasn’t like Pinkie was in any condition to hear him. Still, in anticipation of this going well, he had prepared a little speech, and maybe she’d remember it once her brain stopped exploding.

“That’s it you little slut. Now you know the truth, you’re nothing but a cum-bucket. Surrender to my stallionhood and revel in your new reality. Soon all the mares of Ponyville, and then Equestria, will assume their rightful place in life.”

“I don’t think so, Monster,” a familiar, and horribly out of place voice, said. Startled out of his wits Dusk twisted his head, just in time to take a blow from the heavy wrench Pinkie Pie had brought into the lab smack across his forehead. His lights went out as he was sent flying backward, his spurting cock yanking loose from Pinkie’s twitching pussy. His body impacted against the bench holding, among other things, the antidote for his current transformation. It, and a large amount of other glassware went crashing to the floor.

Rarity Belle, in full avenging mode felt a thrill of victory as she saw her foe so easily dispatched. Her emotions turned to frantic worry as she hurried across the lab from the base of the stairs to render aid to poor Pinkie Pie who had suffered so grievously at the hooves of the monster Rarity had just rendered unconscious.

It looked like Rainbow Dash was not just spouting nonsense after all. Equestria really was being invaded by male doppelgangers of their friends. She could only hope that Rainbow Dash would discover Twilight during her rescue attempt of poor Fluttershy. For the time being, Rarity had a villain to question, once she had freed and offered comfort to Pinkie Pie that is.

Author's Notes:

Uhoh, is this the end of poor Dusk Shine's rise? Or will Rarity receive chastisement for her impulsive action.